As stated in the above applications and patent, an anti-theft locking mechanism for a vehicle is enabled by an authorized person (e.g., owner) and set by an unauthorized person (e.g., thief) and, if associated with an original equipment hydraulic system, includes a piston-cylinder combination which may be selectively enabled or reset by owner but which is "set" by the thief, so that, assuming a brake system is involved, the vehicle can not be further driven, nor pushed, nor towed.
It has been found, however, that with the prior arrangements as described in the patent the deterrent might be adequate only as to a first theif (he uses the brakes in traffic but then the wheels lock up and he has to depart on foot). It is desirable to provide a more stationary brake lock, to deter those unauthorized persons who might later try to move the vehicle.
The problem is one of pressure fluid leakage, both internally of the cylinder provided as part of the vehicle lock-up apparatus, as well as externally, from inside to outside the cylinder.
An object of the present invention is to provide inexpensive means for overcoming the above mentioned difficulties, thereby providing more permanent vehicle locking means as well as an improved piston cylinder arrangement for other uses.